Water
Security:
Propeller and
Nautilus
The major concern of drinking water storage
nowadays is microbial contamination. Unlike in
nature where seawater is mixed naturally by
wind circulation and marine organisms,
stagnant water stored in tanks is inadequately
circulated, resulting in temperature
stratification and degradation of the upper
layer, where disinfectant residuals are lost.
Biomimetic entrepreneur Jay Harman noticed the recurrent geometry of threedimensional
centripetal spirals in fluid flows and consequently realised that the most
efficient way to move in water is to move in Phi curves or the Golden Ratio. “PAX
streamlining principle” describes the scalable combined curves in multiple dimensions,
resulting in an organic shape that pulls fluid at the edges to its centre. Lily Impeller is
designed using computational fluid dynamics (CFD) to reverse engineer and simulate
vertical whirlpool flows in nature. Mimicking the centripetal inward-motioned spiral in
nautilus, the impeller is able to minimise drag and resistance, and reduce noise pollution.
An energy-efficient “organised turbulence” is constantly generated by the small
ring-shaped vortex placed in the middle of the pool. Efficient mechanical mixing using the
Lily Impellers would discourage the bacterial proliferation, reducing the need for
artificial disinfectants that can produce harmful by-products that link to cancer and
other developmental health risks. [2] The propeller design sets an example of how
hydrodynamic structures can improve efficiency by looking at the outcomes of nature’s
research.